[0001] The present invention generally relates to remote lecturing systems, and more particularly
to a remote lecturing system which enables a student to receive at a station, not
in real time, a lecture which is held by a lecturer. In particular, the present invention
relates to a remote lecturing system characterized in that there are provided first
storage means arranged to store content-s of at least one lecture of a lecturer; second
storage means arranged to store questions and corresponding answers related to each
lecture stored in said first storage means; reproducing means, coupled to said first
storage means, arranged to retrieve from said first storage means the contents of
an arbitrary lecture which is requested in response to an external request from a
first terminal station which is operated by a student at an arbitrary time, and further
arranged to transfer the retrieved contents to the first terminal station; and answer
obtaining means, coupled to said second storage means, for retrieving from said second
storage means an answer which corresponds to a question from the first terminal station.
Such a remote lecturing system is disclosed in FUNKSCHAU, vol. 62, no. 13, July 1990,
pages 34, 36, 39, 40, München, DE; E. IHM: "Funline ersetzt die Schulbank", page 39,
chapter "Der direkte Draht zum Lehrer oder Autor"; figures 5-7.
[0002] Reference is also made to US-A-971,141, which discloses an interactive lecture system.
Tapes of lectures and answers to commonly asked questions are sent manually to users,
for loading into the lecturing system. A lecture map is also provided to give an outline
of the lecture topics and to enable the answers to particular questions to be ascertained.
A user can manually interrupt the lecture, obtain answers to questions, and then go
directly back to the place where he left off the lecture without losing his place.
[0003] Lecturing systems which use a communication network are becoming popular. For example,
a computer aided learning (CAL) enables a student to receive a lecture which is held
by a lecturer via a communication network. However, such lecturing systems require
the lecturer and the student to communicate in real time. For this reason, there are
demands to realize a remote lecturing system which enables the student to receive
the lecture not in real time, that is, at an arbitrary time.
[0004] The conventional remote lecturing systems may roughly be divided into two kinds.
According to the first kind, the lecture held by the lecturer is transferred to the
student in real time, and the student receives the audio and/or visual information
of the lecture. On the other hand, according to the second kind, the lecturer records
the lecture on a video tape recorder (VTR) or the like, and the student later makes
access to the recorded lecture at an arbitrary time.
[0005] However, according to the first kind of remote lecturing system, both the lecturer
and the student must avail themselves at the same time. For this reason; this remote
lecturing system lacks flexibility in that the time and day of the lecture must be
determined to suit the schedules of all persons concerned, that is, the lecturer and
all of the students.
[0006] On the other hand, according to the second kind of remote lecturing system, the lecturer
simply needs to record the lecture, and each student can make access to the recorded
lecture at an arbitrary time. Hence, the lecturer and the students have no need to
make a mutually convenient time for the lecture. But since the lecture is prerecorded,
there is a problem in that the student cannot obtain an answer to his question when
he receives the lecture. Usually, the student will have difficulty understanding the
rest of the lecture when his questions are unanswered. Therefore, the fact that the
student cannot obtain an answer to his question is a big problem to the remote lecturing
system.
[0007] Accordingly, it is a general object of the present invention to provide a novel and
useful remote lecturing system in which the problems described above are eliminated.
[0008] The invention relates to a remote lecturing system as initially defined, characterized
in that said answer obtaining means is arranged to interrupt the transfer of the contents
of the arbitrary lecture from said reproducing means to the first terminal station
when the question is raised from the first terminal station.
[0009] According to the remote lecturing system of the present invention, the student can
receive a desired lecture at an arbitrary time, and also obtain answers to his questions
raised during the lecture in real time when possible.
[0010] The present invention will be understood from the following detailed description,
given by way of example and with reference to the accompanying drawings, in which:-
FIG.1 is a system block diagram for explaining an operating principle of a remote
lecturing system according to the present invention;
FIG.2 is a system block diagram showing a first embodiment of the remote lecturing
system according to the present invention;
FIG.3 is a flow chart for explaining an operation of the first embodiment;
FIG.4 shows a Q/A file used in the first embodiment;
FIG.5 shows a table of lecturer's whereabouts;
FIG.6 is a flow chart showing an essential part of the operation of a second embodiment
of the remote lecturing system according to the present invention;
FIG.7 is a flow chart showing an essential part of the operation of a third embodiment
of the remote lecturing system according to the present invention;
FIG.8 is a flow chart showing an essential part of the operation of a fourth embodiment
of the remote lecturing system according to the present invention;
FIG.9 is a flow chart for explaining an embodiment of a Q/A tool;
FIG.10 shows a Q/A file used by the Q/A tool;
FIG.11 shows a keyword matching table used by the Q/A tool;
FIG.12 is a system block diagram showing a fifth embodiment of the remote lecturing
system according to the present invention; and
FIG.13 is a flow chart for explaining a sixth embodiment of the remote lecturing system
according to the present invention.
[0011] First, a description will be given of an operating principle of a preferred remote
lecturing system according to the present invention, by referring to FIG.1.
[0012] In FIG.1, a center station 10 includes a first storage 12a for storing contents of
lectures in a coded form, a second storage 12b for storing questions and answers in
a coded form, a lecture reproducing part 14, and an answer obtaining part 15. The
center station 10 is coupled to a communication line (not shown), and relays the contents
of a lecture to a student not in real time, that is, at an arbitrary time, and also
provides answers to questions raised by the student.
[0013] The lecture reproducing part 14 makes access to the first storage 12a and retrieves
the lecture which is requested by the student. The contents of the retrieved lecture
are decoded, and the reproduced contents of the lecture are transferred to a terminal
station of the student via the communication line.
[0014] When the student raises a question during the lecture, the answer obtaining part
16 interrupts the lecture reproducing part 14 and makes an access to the second storage
12b. The answer obtaining part 16 retrieves the registered questions from the second
storage 12b to decide whether or not the question raised by the student is already
registered in the second storage 12b. If the question raised by the student is registered
in the second storage 12b, the answer obtaining part 16 retrieves a corresponding
answer from the second storage 12b and transfers this answer to the terminal station
of the student. On the other hand, if the question raised by the student is not registered
in the second storage 12b, the answer obtaining part 16 makes contact with the lecturer
so that the answer can be transferred promptly to the terminal station of the student.
After the answer obtaining part 16 transfers the registered answer to the terminal
station of the student or makes contact with the lecturer, the answer obtaining part
16 restarts the lecture reproducing part 14 so as to continue the lecture.
[0015] For example, the student who is authorized to make access to a lecture sends a password
from his terminal station to the center station 10. When the authorized student is
correctly identified from the password, the lecture reproducing part 14 makes access
to the first storage 12a as indicated by an arrow "1" so as to reproduce the requested
lecture. The contents of the lecture are reproduced and transferred to the terminal
station of the student as indicated by an arrow "2".
[0016] If the student has a question during the lecture, the student sends a password which
indicates a question from his terminal station to the center station 10 as indicated
by an arrow "3". When the question is correctly identified from the password, the
answer obtaining part 16 interrupts the lecture reproducing part 14 as indicated by
an arrow "4" so as to temporarily stop the lecture. The answer obtaining part 16 decides
whether or not the question is a new question, that is, a question which is not yet
registered in the second storage 12b, by making access to the second storage 12b as
indicated by an arrow "5".
[0017] If the question is already registered in the second storage 12b, the answer obtaining
part 16 retrieves a corresponding answer from the second storage 12b as indicated
by an arrow "6", and transfers this answer to the terminal station of the student
as indicated by an arrow "7". On the other hand, if the question is not registered
in the second storage 12b, the answer obtaining part 16 makes contact with the lecturer
and obtains the answer to the question as indicated by an arrow "8", and this answer
is transferred to the terminal station of the student as indicated by the arrow "7".
Of course, the lecturer may not be available immediately, and in such a case, the
answer which is later obtained from the lecturer is stored in the second storage 12b
so that the student can obtain the answer after the lecture, for example. After transferring
the answer to the terminal station of the student or informing the student that the
answer will be available later, the answer obtaining part 16 restarts the lecture
reproducing part 14 so as to resume the lecture from where it was interrupted by the
student's question.
[0018] Next, a description will be given of a first embodiment of the remote lecturing system
according to the present invention, by referring to FIG.2. In FIG.2, those parts which
are the same as those corresponding parts in FIG.1 are designated by the same reference
numerals, and a description thereof will be omitted.
[0019] In FIG.2, the center station 10 is coupled to terminal stations 40 and 50 of students
and to a terminal station 60 of a lecturer via a communication network 30. The center
station 10 includes the first and second storages 12a and 12b, the lecture reproducing
part 14, a lecture recording part 15, the answer obtaining part 16 and a transmitter/receiver
part 18 which are coupled as shown. The transmitter/receiver part 18 is coupled to
the communication network 30. The answer obtaining part 16 includes a data management
part 21, a lecturer calling part 22 and a table 23 of lecturer's whereabouts.
[0020] The center station 10 can provide a lecture which is requested from the terminal
station 40 or 50 of the student via the communication network 30. The center station
10 can provide the requested lectures to the independent terminal stations 40 and
50 because the contents of the lectures are stored in the first storage 12a as described
above.
[0021] A lecturer may record his lecture by transmitting the lecture from the terminal station
60 to the center station 10. At the center station 10, the received lecture is supplied
to the lecture recording part 15 via the transmitter/receiver 18, and the lecture
recording part 15 codes the contents of the lecture. The recording part 15 then stores
the contents of the lecture in the first storage 12a in the form of codes.
[0022] For example, the first storage 12a is made up of a magnetic disk unit, and the contents
of the lectures are recorded on a magnetic disk of the magnetic disk unit. Similarly,
the second storage 12b is also made up of a magnetic disk unit, and the questions
and the corresponding answers are recorded on a magnetic disk of the magnetic disk
unit. When a question made by the student is a new question and is not yet registered
in the second storage 12b, the new question and a corresponding answer are additionally
recorded in the second storage 12b, as will be described later.
[0023] The lecture reproducing part 14 retrieves from the first storage 12a the lecture
which is requested by the student, and transmits the contents of the requested lecture
to the terminal station 40 or 50 of the student. In other words, the lecture reproducing
part 14 has a function of retrieving the requested lecture from the first storage
12a, a function of transmitting the contents of the requested lecture to the terminal
station 40 or 50, and a function of controlling the transmission, that is, starting,
interrupting and resuming the transmission of the lecture contents.
[0024] The data management part 21 of the answer obtaining part 16 has four basic functions.
[0025] The first function of the data management part 21 detects a question from the student
when the student transmits a certain questioning keyword from the terminal station
40 or 50. For example, when the questioning keyword is "NW,DMIX", the first function
detects this question and transmits an answer related to a function of DMIX, as will
be described with regard to the third and fourth functions.
[0026] The second function of the data management part 21 interrupts the lecture reproducing
part 14 when the question is detected, so as to interrupt the lecture, and searches
for this question in the second storage 12b so as to decide whether or not this question
is a completely new question which is not yet registered in the second storage 12b.
For example, in the above described case where the student raises the question related
to the function of the DMIX, the second function decides whether or not this question
is new.
[0027] The third function of the data management part 21 selects the questioning keyword
received from the student if the question raised by the student is decided by the
second function as not being a new question, that is, decided as being already registered
in the second storage 12b, and retrieves a corresponding answer to this question from
the second storage 12b. In other words, the corresponding answer is retrieved from
the second storage 12b by making access using the questioning keyword. The retrieved
answer is transmitted to the terminal station 40 or 50 of the student via the transmitter/receiver
18. Of course, the data management part 21 may instruct the lecture reproducing part
14 to transmit the answer.
[0028] The fourth function of the data management part 21 stores the question raised by
the student in the second storage 12b if the second function decides the question
as being new. In addition, the data management part 21 starts the lecturer calling
part 22. The lecturer calling part 22 retrieves the whereabouts of the lecturer from
the table 23 which stores information related to the possible whereabouts of the lecturer
including the terminal station 60 which is located near the lecturer's present location.
The present location of the lecturer can be retrieved from the table 23 depending
on the present time and day, for example, and the lecturer calling part 22 automatically
makes contact with the lecturer via the terminal station 60. Of course, the table
23 may store the whereabouts of a plurality of lecturers, but the lecturer of the
present lecture which is being provided to the student can easily be identified from
the lecture.
[0029] When making contact with the lecturer, the data management part 21 transmits the
new question to the terminal station 60 via the transmitter/receiver 18. Of course,
the data management part 21 may instruct the lecture reproducing part 14 to transmit
the new question to the terminal station 60. The lecturer prepares an answer to the
new question, and transmits the answer to the center station 10.
[0030] The fifth function of the data management part 21 registers the new question and
the corresponding answer which is received from the terminal station 60 in the second
storage 12b. In addition, the answer to the new question is transmitted to the terminal
station 40 or 50 via the data management part 21. Of course, the data management part
21 may instruct the lecture reproducing part 14 to transmit the answer to the terminal
station 40 or 50.
[0031] The sixth function of the data management part 21 decides whether or not the student
is satisfied with the answer supplied in response to his question. For example, it
is decided that the answer satisfies the student when no further questions are raised
by the student. The data management part 21 restarts the lecture reproducing part
14 when the answer satisfies the student, so as to resume the lecture from where it
was interrupted by the question.
[0032] Of course, if the lecturer is not available immediately to answer the new question,
the data management part 21 may inform the student that the answer to his question
will be registered within a predetermined time. In this case, the student may elect
to resume receiving the rest of the lecture, or resume receiving the lecture at a
convenient time which is after the predetermined time so that his new question may
be answered before receiving the rest of the lecture.
[0033] In any case, answers to more questions will be registered in the second storage 12b
as more and more questions are raised by students who receive the lecture, and the
lecture as a whole will be improved with time.
[0034] Next, a description will be given of the operation of the first embodiment, by referring
to the flow chart of FIG.3.
[0035] In FIG.3, a step 301 stores the contents of a lecture made by a lecturer in the first
storage 12a in a form of a lecture file. This lecture file includes codes, dots, audio
and video information. Hence, the first storage 12a stores a plurality of such lecture
files corresponding to various lectures. For example, the contents of the lecture
are transmitted from the terminal station 60 to the center station 10 via the communication
network 30.
[0036] When the student makes a request to receive a lecture from the terminal station 40
as indicated by an arrow A1 in FIG.2, a step 302 provides the requested lecture to
the student. The contents of the requested lecture are read from the first storage
12a and transmitted to the terminal station 40 of the student as indicated by an arrow
A2 in FIG.2.
[0037] The student may raise a question during the lecture. In this case, the student sends
a questioning keyword "NW,DMIX" for example, to the center station 10 as indicated
by a dotted arrow A3 in FIG.2. Hence, a step 303 interrupts the lecture in response
to the questioning keyword "NW,DMIX". For example, as shown in FIG.4, a Q/A file of
the second storage 12b includes "NW,DMIX" which is is written in a questioning keyword
column 41, ""function of DMIX is ..." which is written in an answer column 42, and
a "lecturer Mr. Smith" written in an answering lecturer column 43.
[0038] Hence, a step 304 collates the questioning keyword "NW,DMIX" with the questioning
keywords which are registered in the questioning keyword column 41 of the Q/A file
in the second storage 12b. When the matching questioning keyword "NW,DMIX" is found
in the questioning keyword column 41, the step 304 retrieves the corresponding answer
"function of DMIX is ..." from the answer column 42 of the Q/A file, and transmits
this answer to the student as indicated by a dotted arrow A4 in FIG.2.
[0039] After transmitting the answer to the terminal station 40 of the student, a step 305
decides whether or not the student is satisfied with the answer. For example, it may
be decided that the student is satisfied with the answer when no further questions
are raised by the student within a predetermined time and that the student is not
satisfied with the answer when a next questioning keyword is received from the terminal
station 40 within the predetermined time.
[0040] In the above described case, the answer to the student's question is already registered
in the Q/A file of the second storage 12b, and thus, the decision result in the step
305 is YES. In this case, a step 307 resumes the lecture which was interrupted by
the question, by transmitting the remaining contents of the lecture to the terminal
station 40 as indicated by an arrow A5 in FIG.2, and the process ends after the step
307.
[0041] However, the student may not be satisfied by the answer which is provided. It may
be that the answer provided does not fully answer his question, or that his question
and corresponding answer are not yet registered in the Q/A file of the second storage
12b. In this case, the decision result in the step 305 is NO, and a step 306 makes
contact with the lecturer by calling the terminal station 60 as indicated by an arrow
A6 in FIG.2. When the lecturer is present at the terminal station 60, the lecturer
transmits the answer to the new question from the terminal station 60 to the center
station 10 as indicated by an arrow A6' in FIG.2.
[0042] The lecturer may be located using the table 23 of the lecturer's whereabouts. FIG.5
shows the contents of the table 23. In FIG.5, "NWK Design" is written in a lecture
name column 51, "Lecturer Mr. Smith" is written in a lecturer column 52, and a telephone
number "XXX-XXX-XXXX" is written in a telephone number column 53. Accordingly, the
telephone number of the terminal station 60 of the lecturer may be found from the
table 23 using the lecturer's name or the lecture name.
[0043] The step 306 transmits the answer received from the terminal station 60 to the terminal
station 40 of the student. In other words, when the lecturer is located immediately,
the answer to the new question is transmitted to the student in real time. In addition,
the step 306 registers the answer obtained from the terminal station 60 in the Q/A
file of the second storage 12b together with the questioning keyword of this new question
which was previously not registered, as indicated by an arrow A7 in FIG.2.
[0044] After the new question and answer are registered in the Q/A file of the second storage
12b, the step 307 resumes the lecture which was interrupted by the question, by transmitting
the remaining contents of the lecture to the terminal station 40 as indicated by an
arrow A8 in FIG.2, and the process ends after the step 307.
[0045] Of course, instead of advancing to the step 307 after the step 306, it is possible
to return to the step 305 after the step 306.
[0046] Therefore, according to this embodiment, the student can receive a desired lecture
at a desired time, that is, not in real time, because the first storage 12a within
the center station 10 stores the various lectures. In addition, since possible questions
and corresponding answers are stored in the Q/A file of the second storage 12b, an
answer can automatically be provided to the student when he raises a question similar
to one of the questions which are already stored in the Q/A file. Furthermore, if
a new question is raised, the Q/A file is improved by storing the new question and
the corresponding answer in the Q/A file after obtaining the answer to this new question
from the lecturer.
[0047] Next, a description will be given of a second embodiment of the remote lecturing
system according to the present invention, by referring to FIG.6.
[0048] FIG.6 shows steps corresponding to the step 301 shown in FIG.3, and a description
and illustration of the remaining steps 302 through 307 will be omitted. In FIG.6,
the lecturer makes a lecture, and a step 3010 receives the lecture from the terminal
station 60, for example. A step 3011 decides whether or not the lecture is to be transmitted
in real time. When the decision result in the step 3011 is YES, a step 3012 starts
transmitting the lecture via the communication network 30, in real time, to the concerned
terminal stations 40 and 50, for example. On the other hand, when the decision result
in the step 3011 is NO, or after the step 3012, a step 3013 stores the contents of
the lecture in the lecture file of the first storage 12a.
[0049] Next, a description will be given of a third embodiment of the remote lecturing system
according to the present invention, by referring to FIG.7.
[0050] FIG.7 shows steps corresponding to the step 302 shown in FIG.3, and a description
and illustration of the remaining steps 301 and 303 through 307 will be omitted. In
FIG.7, the student makes a request from the terminal station 40, for example, to receive
the desired lecture in a step 3020. A step 3021 decides whether or not data related
to the desired lecture are already stored in the terminal station 40. In other words,
the contents of one or a plurality of lectures may already be transferred from the
center station 10 and stored in the terminal station 40, because the student may not
be the first student to use the terminal station 40. When the decision result in the
step 3021 is NO, a step 3022 requests transfer of the contents of the desired lecture
from the center station 10 to the terminal station 40, and a step 3023 starts the
desired lecture based on the contents which are transferred from the center station
10 and stored in the terminal station 40. On the other hand, when the decision result
in the step 3021 is YES, a step 3024 retrieves the contents of the desired lecture
which are already stored in the terminal station 40, and the step 3023 starts the
desired lecture based on the previously stored contents of the desired lecture.
[0051] Next, a description will be given of a fourth embodiment of the remote lecturing
system according to the present invention, by referring to FIG.8.
[0052] FIG.8 shows steps corresponding to the steps 303, 304, 305 and 306 shown in FIG.3,
and a description and illustration of the remaining steps 301, 302, and 307 will be
omitted. In FIG.8, the student raises a question and a step 401 inputs the question.
A step 402 decides whether or not a lecture is being made. The lecture may be made
in real time or not in real time. When the decision result in the step 402 is YES,
a step 403 interrupts the lecture. After the step 403 or when the decision result
in the step 402 is NO, a step 404 operates a Q/A tool. As will be described later
in more detail, the Q/A tool is used to obtain a corresponding answer to the question
and to transmit the answer to the student.
[0053] A step 405 decides whether or not the answer satisfies the student. When the decision
result in the step 405 is YES, a step 406 decides whether or not a lecture was being
made. When the decision result in the step 406 is YES, a step 407 resumes the lecture.
The process ends after the step 407 or when the decision result in the step 406 is
NO.
[0054] On the other hand, when the decision result in the step 405 is NO, a step 408 decides
whether or not the lecture is being made in real time. When the decision result in
the step 408 is NO, a step 409 calls the lecturer using the table 23 described above.
On the other hand, when the decision result in the step 408 is YES or after the step
409, the lecturer provides the answer in real time and a step 410 inputs this answer
from the lecturer. Then, a step 411 transmits the answer from the lecturer to the
student, and the process returns to the step 404.
[0055] Next, a description will be given of an embodiment of the Q/A tool which is used
in the step 404 shown in FIG.8, by referring to FIG.9.
[0056] In FIG.9, a step S1 inputs the student's question which is in the form of a natural
speech. A step S2 decomposes the question into parts of speech, and forms keywords
from main elements of the speech such as nouns and verbs. Then, a step S3 compares
the group of keywords which are formed with keywords stored under a keyword column
of a Q/A file shown in FIG.10, and forms a keyword matching table shown in FIG.11
which indicates the number of matching keywords in the Q/A file with respect to the
question.
[0057] A step S4 decides whether or not an answer which corresponds to the question exists
in the Q/A file. When the decision result in the step S4 is YES, a step S5 selects
one or more answers which have the largest number of matching keywords. A step S6
decides whether or not there is only one answer. When the decision result in the step
S6 is YES, a step S7 transfers the only answer to the student.
[0058] On the other hand, when the decision result in the step S6 is NO, a step S8 decides
whether or not a remaining keyword without a match exists in the question. When the
decision result in the step S8 is NO, a step S9 selects and makes contact with a lecturer
who can answer the student's question and urges the lecturer to add a keyword for
distinguishing the two or more answers. After the step S9 or when the decision result
in the step S8 is YES, a step S10 urges the student to indicate which one of the remaining
keywords is pertinent to his question, or to input a hint which would help correctly
identify his question if none of the remaining keywords are pertinent. A step S11
selects the answer which is related to the keyword indicated by the student, or the
hint input by the student, out of the two more more candidate answers. A step S12
transfers the selected answer to the student.
[0059] On the other hand, when the decision result in the step S4 is NO, a step S13 selects
and makes contact with the lecturer who can answer the student's question, and informs
the lecturer of the student's question so that the lecturer may transfer an answer.
A step S14 registers the new question, the corresponding answer from the lecturer
and the related keywords in the Q/A file. In addition, a step S15 transfers the answer
which is obtained from the lecturer to the student.
[0060] A step S16 decides whether or not the answer transferred to the student is satisfactory
to the student. This step S16 is carried out after the step S7, S12, S15 or S18 which
will be described later. The process ends when the decision result in the step S16
is YES. But when the decision result in the step S16 is NO, a step S17 makes contact
with the lecturer and informs the lecturer of the student's question and the answer
which is transferred to the student, so that the lecturer may provide a new answer
which more fully answers the student's question. In this case, a new keyword is added
to the new answer so that the new answer may be distinguished from the answer which
was previously transferred to the student. Thereafter, the step S18 transfers the
new answer to the student.
[0061] Next, a description will be given of the remaining keywords, by referring to a particular
example.
[0062] For example, the student raises a question (a) which is "When and where was the intelligent
network developed ?", and this question (a) is input in the step S1 shown in FIG.9.
The step S2 decomposes this question (a) into a group (b) of keywords which are "When",
"where", "intelligent network" and "developed". FIG.10 shows the Q/A file which is
used in this particular example. The step S3 searches for matching keywords in the
Q/A file shown in FIG.10, and forms the keyword matching table shown in FIG.11.
[0063] In FIG.10, an answer (c) has an answer number "1" and states "The intelligent network
(IN) was developed in the United States in 1985", an answer (d) has an answer number
"3" and states "The intelligent network has an abbreviation IN and was developed in
the United States in 1985.", and an answer (e) has an answer number "5" and states
"The intelligent network (IN) provides a control center to a public line to make it
look like a leased line, and was developed in the United States in 1985.".
[0064] It may be seen from the keyword matching table that rows (A) and (B) have the largest
number of matching keywords. Hence, the step S10 uses the remaining keywords to urge
the student to select one of the remaining keywords which are pertinent to his question,
or to input a hint which will help identify his question. In this case, the following
message may be transferred to the student.
"Select one keyword most pertinent to your question, and input hint if none are pertinent."
(1) Abbreviation
(2) Definition
(3) Other
[0065] If the student selects the keyword (2) which is "Definition", the answer to his question
is most likely in the row (B) shown in FIG.11. Thus, the answer number "5" is retrieved
from the Q/A file and the corresponding answer (e) is transferred to the student.
In this case, the answer (e) is "The intelligent network (IN) provides a control center
to a public line to make it look like a leased line, and was developed in the United
States in 1985.".
[0066] Next, a description will be given of a fifth embodiment of the remote lecturing system
according to the present invention, by referring to FIG.12.
[0067] In this embodiment, a terminal station 901 of a lecturer and terminal stations 902
1 through 902
N of students are coupled via a ground communication network 903. A synchronous satellite
904 functions as the center station 10 shown in FIG.2. The lecture contents are transmitted
from the terminal station 901 to the satellite 904 and stored in the first storage
of the satellite 904. The lecture is broadcast from the satellite 904 to all of the
terminal stations 902
1 through 902
N.
[0068] When a student raises a question from the terminal station 902
1, for example, this question is once transmitted to the terminal station 901 via the
network 903, and the question is transmitted to the satellite 904 so that the question
is broadcast to all of the terminal stations 902
1 through 902
N. An answer provided by the lecturer is thereafter transmitted to the satellite 904
and the answer is broadcast to all of the terminal stations 902
1 through 902
N. In FIG.12, solid arrows indicate the flow of the lecture contents, and dotted arrows
indicate the flow of the questions and answers. According to this embodiment, all
of the students become aware of a question raised by one student, and all of the students
become aware of an answer provided by the lecturer in response to the question.
[0069] Next, a description will be given of a sixth embodiment of the remote lecturing system
according to the present invention, by referring to FIG.13. As explained in the third
embodiment in conjunction with FIG.7, a distant terminal station of the student may
receive the lecture contents and the contents of the Q/A tool from the center station
by a high-speed file transfer and store these contents in advance. In this case, when
the student makes a request to receive a certain lecture, the terminal station simply
needs to obtain from the center station contents which are related to this certain
lecture and are not stored in the terminal station. In many cases, the Q/A tool is
constantly revised and improved, and it is desirable to check whether or not the related
Q/A tool stored in the terminal station is an updated version.
[0070] In FIG.13, a step S31 requests the certain lecture from the terminal station. A step
S32 decides whether or not the data related to the certain lecture are stored in the
terminal station. When the decision result in the step S32 is YES, a step S33 checks
the version number of the data related to the certain lecture. A step S34 decides
whether or not the version number is too old for use. When the decision result in
the step S34 is NO, a step S35 starts receiving the lecture based on the stored data
in the terminal station.
[0071] On the other hand, when the decision result in the step S32 is NO or the decision
result in the step S34 is YES, a step S36 requests the necessary data related to the
certain lecture to the center station. At the center station, a step S37 retrieves
the necessary data related to the certain lecture and transfers the data to the terminal
station. At the terminal station, a step S38 receives the necessary data from the
center station, and and a step S39 updates the data stored in the terminal station.
Thereafter, the step S35 starts receiving the certain lecture based on the newly stored
data in the terminal station.
[0072] In each of the embodiments described heretofore, the number of students attending
the lecture at the terminal station is of course not limited to one.
[0073] Further, the present invention is not limited to these embodiments, but various variations
and modifications may be made without departing from the scope of the present invention.
[0074] Reference signs in the claims are intended for better understanding and shall not
limit the scope.
1. A remote lecturing system in which there are provided:
first storage means (12a) arranged to store contents of at least one lecture of a
lecturer;
second storage means (12b) arranged to store questions and corresponding answers related
to each lecture stored in said first storage means;
reproducing means (14), coupled to said first storage means, arranged to retrieve
from said first storage means the contents of an arbitrary lecture which is requested
in response to an external request from a first terminal station (40, 50, 9021-902N) which is operated by a student at an arbitrary time, and further arranged to transfer
the retrieved contents to the first terminal station; and
answer obtaining means (16), coupled to said second storage means, for retrieving
from said second storage means an answer which corresponds to a question from the
first terminal station
characterized in that said answer obtaining means (16) is arranged to interrupt
the transfer of the contents of the arbitrary lecture from said reproducing means
to the first terminal station when the question is raised from the first terminal
station.
2. The remote lecturing system as claimed in claim 1, characterized in that said answer
obtaining means (16) is arranged to resume the transfer of the contents of the arbitrary
lecture from said reproducing means (14) to the first terminal station (40, 50, 9021-902N) when no further questions are raised from the first terminal station.
3. The remote lecturing system as claimed in claim 1 or 2, characterized in that said
answer obtaining means (16) includes calling means (22)arranged to automatically call
a lecturer of the arbitrary lecture when no answer corresponding to the question is
retrieved from said second storage means (12b).
4. The remote lecturing system as claimed in claim 3, characterized in that said calling
means (22) of said answer obtaining means (16)is arranged to transfer an answer received
from the lecturer to the first terminal station (40, 50, 9021-902N).
5. The remote lecturing system as claimed in claim 4, characterized in that said calling
means (22) of said answer obtaining means (16) is arranged to transfer the answer
received from the lecturer to the first terminal station (40, 50, 9021-902N) in real time.
6. The remote lecturing system as claimed in claim 4 or 5, characterized in that said
answer obtaining means (16) further includes means (21) arranged to store the question
raised from the first terminal station (40, 50, 9021-902N) in said second storage means (12b) together with the answer obtained from the lecturer.
7. The remote lecturing system as claimed in claim 6, characterized in that said reproducing
means (14) and said answer obtaining means (16) are coupled to the first terminal
station (40, 50) via a communication network (30), said communication network being
coupled to at least a second terminal station (60, 901) which is arranged to be operated
by the lecturer.
8. The remote lecturing system as claimed in claim 7, characterized in that said calling
means (22) of said answer obtaining means (16) is arranged to call the lecturer of
the arbitrary lecture by calling the second terminal station (60) via the communication
network (30).
9. The remote lecturing system as claimed in any one of claims 1 to 8, characterized
in that there is further provided recordingmeans (15) arranged to record contents
of a lecture in said first storage means (12a).
10. The remote lecturing system as claimed in any one of claims 1 to 9, characterized
in that said reproducing means (14) and said answer obtaining means (16) are coupled
to the first terminal station (40, 50) via a communication network (30), said communication
network being coupled to a plurality of terminal stations (40, 50, 60), said reproducing
means being arranged to broadcast the arbitrary lecture to the terminal stations which
are coupled to the communication network, and said answer obtaining means being arranged
to broadcast the question and the corresponding answer to the terminal stations which
are coupled to the communication network.
11. The remote lecturing system as claimed in any one of claims 1 to 10, characterized
in that said answer obtaining means (16) is arranged to collate keywords included
in the question from the first terminal station (40, 50, 9021-902N) with keywords of the questions and answers stored in said second storage means (12b)
and is arranged to retrieve a candidate answer which corresponds to a question with
a largest number of matching keywords as the answer to the question from the first
terminal station.
12. The remote lecturing system as claimed in claim 11, characterized in that, when said
answer obtaining means (16) retrieves a plurality of candidate answers corresponding
to predetermined questions with the largest number of matching keywords, said answer
obtaining means is arranged to transfer to the first terminal station (40, 50, 9021-902N) keywords of the predetermined questions not matching the keywords of the question
from the first terminal station, so that a a keyword most pertinent to the question
from the first terminal station may be selected at the first terminal station.
13. The remote lecturing system as claimed in any of claims 1 to 12, characterized in
that said first and second storage means (12a, 12b), said reproducing means (14) and
said answer obtaining means (16) form a center station (10) which is coupled to a
communication network (30), said reproducing means and said answer obtaining means
are coupled to the communication network, and said communication network is coupled
to the first terminal station (40, 50) and at least a second terminal station (60)
which is arranged to be operated by the lecturer.
14. The remote lecturing system as claimed in any of claims 1 to 12, characterized in
that said first and second storage means (12a, 12b), said reproducing means (14) and
said answer obtaining means (16) form a center station (10) which is provided in a
synchronus satellite (904), said center station being arranged to communicate with
the first terminal station (9021-902N) and at least a second terminal station which is arranged to be operated by the lecturer
(901), and said first and second terminal stations are coupled via a ground communication
network (903).
15. The remote lecturing system as claimed in any of claims 1 to 14, characterized in
that said first terminal station (40, 50, 9021-902N) includes means for storing the contents of at least one lecture transferred from
said reproducing means (14).
1. Ein Fern-Vorlesungssystem, in dem vorgesehen sind:
eine erste Speichervorrichtung (12a), die angeordnet ist, um den Inhalt von mindestens
einer Vorlesung eines Dozenten zu speichern;
eine zweite Speichervorrichtung (12b), die angeordnet ist, um Fragen und entsprechende
Antworten, die aufjede in der ersten Speichervorrichtung gespeicherte Vorlesung bezogen
sind, zu speichern;
eine mit der ersten Speichervorrichtung verbundene Wiedergabevorrichtung (14), die
angeordnet ist, um von der ersten Speichervorrichtung die Inhalte einer beliebigen
Vorlesung wiederzugewinnen, die in Antwort auf eine äußere Anforderung von einem ersten
Bildschirmplatz (40, 50, 9021 - 902N) angefordert wird, die von einem Studenten zu einer beliebigen Zeit bedient wird,
und die weiter angeordnet ist, die wiedergewonnenen Inhalte zu dem ersten Bildschirmplatz
zu übertragen; und
eine mit der zweiten Speichervorrichtung verbundene Vorrichtung zum Erzielen einer
Antwort (16), um von der zweiten Speichervorrichtung eine Antwort, die einer Frage
von dem ersten Bildschirmplatz entspricht, wiederzugewinnen,
dadurch gekennzeichnet, daß die Vorrichtung zum Erzielen einer Antwort (16) angeordnet
ist, um die Übertragung der Inhalte von der beliebigen Vorlesung von der Wiedergabevorrichtung
zu dem ersten Bildschirmplatz zu unterbrechen, wenn die Frage von dem ersten Bildschirmplatz
gestellt wird.
2. Das Fern-Vorlesungssystem gemäß Anspruch 1, dadurch gekennzeichnet, daß die Vorrichtung
zum Erzielen einer Antwort (16) angeordnet ist, die Übertragung der Inhalte der beliebigen
Vorlesung von der Wiedergabevorrichtung (14) zu dem ersten Bildschirmplatz (40, 50,
9021 - 902N) wiederaufzunehmen, wenn keine weiteren Fragen von dem ersten Bildschirmplatz gestellt
werden.
3. Das Fern-Vorlesungssystem gemäß Anspruch 1 oder 2, dadurch gekennzeichnet, daß die
Vorrichtung zum Erzielen einer Antwort (16) eine Rufvorrichtung (22) einschließt,
die angeordnet ist, um automatisch einen Dozenten der beliebigen Vorlesung anzurufen,
wenn von der zweiten Speichervorrichtung (12b) keine der Frage entsprechende Antwort
wiedergewonnen wird.
4. Das Fern-Vorlesungssystem gemäß Anspruch 3, dadurch gekennzeichnet, daß die Rufvorrichtung
(22) der Vorrichtung zum Erzielen einer Antwort (16) angeordnet ist, um eine von dem
Dozenten empfangene Antwort zu dem ersten Bildschirmplatz (40, 50, 9021 - 902N) zu übertragen.
5. Das Fern-Vorlesungssystem gemäß Anspruch 4, dadurch gekennzeichnet, daß die Rufvorrichtung
(22) der Vorrichtung zum Erzielen einer Antwort (16) angeordnet ist, um die von dem
Dozenten empfangene Antwort zu dem ersten Bildschirmplatz (40, 50, 9021 - 902N) in Echtzeit zu übertragen.
6. Das Fern-Vorlesungssystem gemäß Anspruch 4 oder 5, dadurch gekennzeichnet, daß die
Vorrichtung zum Erzielen einer Antwort (16) weiter eine Vorrichtung (21) einschließt,
die angeordnet ist, die von dem ersten Bildschirmplatz (40, 50, 9021 - 902N) gestellte Frage in der zweiten Speichervorrichtung (12b) zusammen mit der von dem
Dozenten erhaltenen Antwort zu speichern.
7. Das Fern-Vorlesungssystem gemäß Anspruch 6, dadurch gekennzeichnet, daß die Wiedergabevorrichtung
(14) und die Vorrichtung zum Erzielen einer Antwort (16) über ein Kommunikationsnetzwerk
(30) mit dem ersten Bildschirmplatz (40, 50) verbunden sind, wobei das Kommunikationsnetzwerk
mindestens mit einem zweiten Bildschirmplatz (60, 901) verbunden ist, welche angeordnet
ist, um von dem Dozenten bedient zu werden.
8. Das Fern-Vorlesungssystem gemäß Anspruch 7, dadurch gekennzeichnet, daß die Rufvorrichtung
(22) der Vorrichtung zum Erzielen einer Antwort (16) angeordnet ist, um den Dozenten
der beliebigen Vorlesung durch Rufen des zweiten Bildschirmplatzes (60) über das Kommunikationsnetzwerk
(30) anzurufen.
9. Das Fern-Vorlesungssystem gemäß der Ansprüche 1 bis 8, dadurch gekennzeichnet, daß
weiter eine Aufzeichnungsvorrichtung (15) vorgesehen ist, die angeordnet ist, um die
Inhalte einer Vorlesung in der ersten Speichervorrichtung (12a) zu speichern.
10. Das Fern-Vorlesungssystem gemäß der Ansprüche 1 bis 9, dadurch gekennzeichnet, daß
die Wiedergabevorrichtung (14) und die Vorrichtung zum Erzielen einer Antwort (16)
mit dem ersten Bildschirmplatz (40, 50) über ein Kommunikationsnetzwerk (30) verbunden
sind, das Kommunikationsnetzwerk mit einer Vielzahl von Bildschirmplätzen (40, 50,
60) verbunden ist, die Wiedergabevorrichtung angeordnet ist, um die beliebige Vorlesung
zu den mit dem Kommunikationsnetzwerk verbundenen Bildschirmplätzen zu übertragen,
und die Vorrichtung zum Erzielen einer Antwort angeordnet ist, um die Frage und die
entsprechende Antwort zu den mit dem Kommunikationsnetzwerk verbundenen Bildschirmplätzen
zu übertragen.
11. Das Fern-Vorlesungssystem gemäß der Ansprüche 1 bis 10, dadurch gekennzeichnet, daß
die Vorrichtung zum Erzielen einer Antwort (16) angeordnet ist, um die in der Frage
von dem ersten Bildschirmplatz (40, 50, 9021 - 902N) enthaltenen Schlüsselwörter mit den Schlüsselwörtern der in der zweiten Speichevorrichtung
(12b) gespeicherten Fragen und Antworten zusammenzustellen und angeordnet ist, um
eine Kandidat-Antwort, welche einer Frage mit der größten Zahl von übereinstimmenden
Schlüsselwörtern entspricht, als die Antwort zu der Frage von dem ersten Bildschirmplatz
wiederzugewinnen.
12. Das Fern-Vorlesungssystem gemäß Anspruch 11, dadurch gekennzeichnet, daß, wenn die
Vorrichtung zum Erzielen einer Antwort (16) eine Vielzahl von Kandidat-Antworten wiedergewinnt,
die mit der größten Zahl von übereinstimmenden Schlüsselwörtern vorherbestimmten Fragen
entsprechen, die Vorrichtung zum Erzielen einer Antwort angeordnet ist, um zu dem
ersten Bildschirmplatz (40, 50, 9021 - 902N) Schlüsselwörter der vorherbestimmten Fragen zu übertragen, die nicht mit den Schlüsselwörtern
der Frage von dem ersten Bildschirmplatz übereinstimmen, so daß ein zu der Frage von
dem ersten Bildschirmplatz am besten passendes Schlüsselwort an dem ersten Bildschirmplatz
ausgewählt werden kann.
13. Das Fern-Vorlesungssystem gemäß der Ansprüche 1 bis 12, dadurch gekennzeichnet, daß
die erste und zweite Speichervorrichtung (12a, 12b), die Wiedergabevorrichtung (14)
und die Vorrichtung zum Erzielen einer Antwort (16) eine Zentralstation (10) bilden,
die mit einem Kommunikationsnetzwerk (30) verbunden ist, die Wiedergabevorrichtung
und die Vorrichtung zum Erzielen einer Antwort mit dem Kommunikationsnetzwerk verbunden
sind, und das Kommunikationsnetzwerk mit dem ersten Bildschirmplatz (40, 50) verbunden
ist und zumindest mit einem zweiten Bildschirmplatz (60), die angeordnet ist, um von
dem Dozenten bedient zu werden.
14. Das Fern-Vorlesungssystem gemäß der Ansprüche 1 bis 12, dadurch gekennzeichnet, daß
die erste und zweite Speichervorrichtung (12a, 12b), die Wiedergabevorrichtung (14)
und die Vorrichtung zum Erzielen einer Antwort (16) eine Zentralstation (10) bilden,
die in einem synchronen Satelliten (904) vorgesehen ist, die Zentralstation angeordnet
ist, um mit dem ersten Bildschirmplatz (9021 - 902N) und zumindest einem zweiten Bildschirmplatz, die angeordnet ist, von dem Dozenten
(901) bedient zu werden, zu kommunizieren, und die erste und zweite Speichervorrichtung
über ein Grund-Kommunikationsnetzwerk (903) verbunden sind.
15. Das Fern-Vorlesungssystem gemäß der Ansprüche 1 bis 14, dadurch gekennzeichnet, daß
der erste Bildschirmplatz (40, 50, 9021 - 902N) eine Vorrichtung zum Speichern der Inhalte von mindestens einer von der Wiedergabevorrichtung
(14) übertragenen Vorlesung einschließt.
1. Système d'enseignement à distance, dans lequel sont prévus:
un premier moyen à mémoire (12a) agencé pour conserver le contenu d'au moins une leçon
d'un enseignant;
un second moyen à mémoire (12b) agencé pour conserver des questions et des réponses
correspondantes concernant chaque leçon conservée dans ledit premier moyen à mémoire;
un moyen de reproduction (14) couplé audit premier moyen à mémoire, agencé pour extraire
dudit premier moyen à mémoire le contenu d'une leçon arbitraire, qui est demandé en
réponse à une demande extérieure provenant d'un premier poste terminal (40, 50, 9021-902N), qui est desservi par un étudiant à un instant arbitraire, et en outre agencé pour
transférer le contenu extrait vers le premier poste terminal; et
un moyen (16) d'obtention de réponses, couplé audit second moyen à mémoire, pour extraire
dudit second moyen à mémoire une réponse qui correspond à une question provenant du
premier poste terminal,
caractérisé en ce que ledit moyen d'obtention de réponses (16) est agencé pour
interrompre le transfert du contenu de la leçon arbitraire dudit moyen de reproduction
au premier poste terminal lorsque la question est posée par ledit premier poste terminal.
2. Système d'enseignement à distance selon la revendication 1, caractérisé en ce que
ledit moyen (16) d'obtention de réponses est agencé pour reprendre le transfert du
contenu de la leçon arbitraire dudit moyen de reproduction (14) au premier poste terminal
(40, 50, 9021-902N) lorsque plus aucune question n'est posée à partir du premier poste terminal.
3. Système d'enseignement à distance selon la revendication 1 ou 2, caractérisé en ce
que ledit moyen (16) d'obtention de réponses contient un moyen d'appel (22) agencé
pour appeler automatiquement un enseignant de la leçon arbitraire lorsqu'aucune réponse
correspondant à la question n'est extraite dudit second moyen à mémoire (12b).
4. Système d'enseignement à distance selon la revendication 3, caractérisé en ce que
ledit moyen d'appel (22) dudit moyen (16) d'obtention de réponses est agencé pour
transférer au premier poste terminal (40, 50, 9021-902N) une réponse reçue de l'enseignant.
5. Système d'enseignement à distance selon la revendication 4, caractérisé en ce que
ledit moyen d'appel (22) dudit moyen (16) d'obtention de réponses est agencé pour
transférer en temps réel la réponse reçue de l'enseignant au premier poste terminal
(40, 50, 9021-902N).
6. Système d'enseignement à distance selon la revendication 4 ou 5, caractérisé en ce
que ledit moyen (16) d'obtention de réponses contient en outre un moyen (21) agencé
pour conserver la question posée à partir du premier poste terminal (40, 50, 9021-902N) dans ledit second moyen à mémoire (12b), en même temps que la réponse obtenue de
l'enseignant.
7. Système d'enseignement à distance selon la revendication 6, caractérisé en ce que
ledit moyen de reproduction (14) et ledit moyen (16) d'obtention de réponses sont
couplés au premier poste terminal (40, 50) par l'intermédiaire d'un réseau de communication
(30), ledit réseau de communication étant couplé à au moins un deuxième poste terminal
(60, 901) qui est agencé pour être desservi par l'enseignant.
8. Système d'enseignement à distance selon la revendication 7, caractérisé en ce que
ledit moyen d'appel (22) dudit moyen (16) d'obtention de réponses est agencé pour
appeler l'enseignant de la leçon arbitraire par appel du second poste terminal (60)
par l'intermédiaire du réseau de communication (30).
9. Système d'enseignement à distance selon l'une quelconque des revendications 1 à 8,
caractérisé en ce qu'il est en outre prévu un moyen d'enregistrement (15) agencé pour
enregistrer le contenu d'une leçon dans ledit premier moyen à mémoire (12a).
10. Système d'enseignement à distance selon l'une quelconque des revendications 1 à 9,
caractérisé en ce que ledit moyen de reproduction (14) et ledit moyen (16) d'obtention
de réponses sont couplés au premier poste terminal (40, 50) par l'intermédiaire d'un
réseau de communication (30), ledit réseau de communication étant couplé à plusieurs
postes terminaux (40, 50, 60), ledit moyen de reproduction étant agencé pour diffuser
la leçon arbitraire vers les postes terminaux qui sont couplés au réseau de communication,
et ledit moyen d'obtention de réponses étant agencé pour diffuser la question et la
réponse correspondante vers les postes terminaux qui sont couplés au réseau de communication.
11. Système d'enseignement à distance selon l'une quelconque des revendications 1 à 10,
caractérisé en ce que ledit moyen (16) d'obtention de réponses est agencé pour confronter
des mots-clé contenus dans la question provenant du premier poste terminal (40, 50,
9021-902N) à des mots-clé des questions et réponses conservés dans ledit second moyen à mémoire
(12b), et est agencé pour extraire une réponse proposée qui correspond à une question
présentant le plus grand nombre de mots-clé correspondants en tant que réponse à la
question provenant du premier poste terminal.
12. Système d'enseignement à distance selon la revendication 11, caractérisé en ce que,
lorsque ledit moyen (16) d'obtention de réponses extrait plusieurs réponses proposées
correspondant à des questions prédéterminées présentant le plus grand nombre de mots-clé
correspondants, ledit moyen d'obtention de réponses est agencé pour transférer au
premier poste terminal (40, 50, 9021-902N) des mots-clé des questions prédéterminées qui ne correspondent pas aux mots-clé
de la question provenant du premier poste terminal, de telle sorte qu'un mot-clé le
plus pertinent par rapport à la question provenant du premier poste terminal puisse
être sélectionné au premier poste terminal.
13. Système d'enseignement à distance selon l'une quelconque des revendications 1 à 12,
caractérisé en ce que ledit premier et ledit second moyens à mémoire (12a, 12b), ledit
moyen de reproduction (14) et ledit moyen (16) d'obtention de réponses forment un
poste central (10) qui est couplé à un réseau de communication (30), ledit moyen de
reproduction et ledit moyen d'obtention de réponses sont couplés au réseau de communication,
et ledit réseau de communication est couplé au premier poste terminal (40, 50) et
à au moins un second poste terminal (60) qui est agencé pour être desservi par l'enseignant.
14. Système d'enseignement à distance selon l'une quelconque des revendications 1 à 12,
caractérisé en ce que ledit premier et ledit deuxième moyens à mémoire (12a, 12b),
ledit moyen de reproduction (14) et ledit moyen (16) d'obtention de réponses forment
un poste central (10) qui est prévu dans un satellite synchrone (904), ledit poste
central étant agencé pour communiquer avec ledit premier poste terminal (9021-902N) et au moins un second poste terminal (901) qui est agencé pour être desservi par
l'enseignant, et ledit premier et ledit deuxième postes terminaux sont couplés par
l'intermédiaire d'un réseau de communication au sol (903).
15. Système d'enseignement à distance selon l'une quelconque des revendications 1 à 14,
caractérisé en ce que ledit premier poste terminal (40, 50, 9021-902N) contient un moyen pour conserver le contenu d'au moins une leçon transféré depuis
ledit moyen de reproduction (14).